Oil separator and method of use



June 2, 1942. i H. A. PHILLIPS OIL SEPARATOR AND METHOD OF USE Filed oct. 1o, i959 Patented June 2, 1942 UNITED STATES PATENT .OFFICE Y 2,235,123 v v on. sEPAaA'roa AND ME'rnon oF 'USE -Harry A. Phillips, Chicago, lll. Application october 10,1939, serial No, 293,755 3 claims. (Cl. s2- 115) l' 'l'his invention relates to an oil separator and `method of using 'samein connection with re-` frigeration apparatus.

' In various types of mechanical refrigeration'l lubricating oil becomes mixed with the refrigverating medium used, 'and it is most important and vdesirable that as much as possible of this oil be prevented from reaching the apparatus in which the work of refrigeration is carried on.

` .Oil has anumber of detrimental effects in the evaporators; among which are the forming of insulating lms on the evaporator surfaces, the

interference with `the proper ebullition and..

' vaporizing of the refrigerantv and .the tendency to dampthe motion of evaporator float controls.

Undue amounts of oil in an evaporator frequently requiresa shut -down and blowing olf of the evaporator to remove such oil deposits.

The viscosity of oilis greatly increased by the cold evaporator temperatures and thus the evaporator itself tends to act as an oil trap, and may require 'frequent cleaning to maintainA efficiency.

Oil separators of various types .have been utilized in refrigeration systems. The methods of operation usually require constant attention -and if any oil is in the system, such methods do not protect the plant" evaporator from being fouled with same.

The presentl apparatus and method has as its principal object the by-passing of the oil around the evaporator so that refrigerant, from which Voil has been separated, is supplied tothe evaporator and thus the ,degree of oil fouling is? materially reduced.

An important object of theinvention is the continual return ofthe separatedoil to the main provision ofa heat exchanger to effect a reducv tion 'in temperature of the mixture prior to the oil separation. Y A further object of thev invention is means operating a thermo controlled -valve to to provide automatically maintain the desired temperature in the separator.

.tor with the surge drum II.

features and advantages- 01.* my improvement will more fully appear in the following description andthe accompanyingdrawing in illustration thereof.

In the drawing Fig. 1 is a diagrammatic elevationof the apparatus used to carry out the invention and shows a heat exchanger in section.

Fig. 2 is a cross section to an enlarged scale of' onejform of oil separator drum to be used in connection with the invention.

Inthe drawing like reference numerals repre-` sent like parts. Referring to Fig. 1, reference numeral IIIy represents an evaporator which may be of any'well known construction. A surge drum II is shown as provided with aefloat control feed valve I2. Pipes I3 and I4 connect the evapora- Pipe I5 conveys vaporized refrigerant from the surge drum II and is connected to the main suction line of .the refrigeration plant. Liquid refrigerant is fed through pipe I6 to the float valvev I2, in accordance-with the load demands of the evaporator I0.

A hand valve II serves to shut off the supply of refrigerant to the evaporator I0. The plant liquid receiver or reservoir for liquid refrigerant is shown at 20, and 2i is a plant liquid line supplying liquid refrigerant to the evaporator I0- from the receiver 20;

An optional heat exchanger is shown at 22 and liquid from the receiver 20 passes throughv reducedto liquid by' the vusual fplant apparatus iiows back to the receiver- 20 to complete its cycle of operation in the well known manner.

Referring to Fig. 2, ythe oil 4separator dr-um 241 comprises the metal shell 30 of cylindrical shape having a head 3I and a bottom 32 to complete the walls of the drum, Attached to the head 3l and extending downwardly within the 'shell 3U is' the internal casing 33. The casing 33 makes a tight joint vat its upper end with the head II and is open to the interior of the shell 30. at its lower end. As anoptianal'variation the lower end of the casing 33 may be filled with steel wool or To these and other ends the characteristic equivalent material as shown at 3l.

The casing 33 is centrally positioned within the shell 30 and the annular space 35 between the two provides room for the cooling coil 36 which.

is wound snugly around the casing 33 and fits snugly within the shell 30. 'I'he upper end of the trol 46 (using an electrical circuit shown diagrammatically at 49) which responds to tem- -perature conditions in the pipe 31, coil 36 and drum 24. Valve 44 acts to modulate the amount of liquid being vaporized through the coil 36. In starting, valve 44 may be kept closed and valve 42 and pipe 43 used to by-pass the valvey 44 and manually control the refrigerating effect in the .inthe drum.

drum 24 is provided with an exit pipe 40 through which the separated liquid passes from the drum 24.

In operation the liquid from the plant receive enters the separator drum 24 through the pipe 23 and flows downwardly within the annular space 35. The helixes of the coil 36 ailord a long path for the liquid and also cause a circular or whirling motion of the liquid which assists in separation of oil from the liquid.

As the mixture of liquid refrigerant and oil passes downwardly through the drum 24 the oil isl congealed and settles toward the bottom of the drum. The clarified liquid moves upwardly into coil 36. When the temperature in the drum 24 is suiilciently reduced, the valve 4| is closed and the valve 44 is used to maintain the temperature Valve 42 may also be used to blow-olf the drum 24 to the suction line I5, and thus remove accumulated deposits from the drum, the coil Y controlled, if preferred, by a customary oat the casing 33, passing through the steel wool 34,

if same is used.

From the casing 33 the liquid passes out of the drum`24, through the pipe 25 and, as shown inl Fig. l, through the heat exchanger 22 in whichA the cold liquid within the pipe 25 absorbs part of the heat 'from the warm liquid coming into the heat exchanger through the pipe 2|. As shown in Fig. 2 the exterior of the drum 24 is covered with insulation 4|.

It will be understood that the oil which passes downwardly in the drum 24 is mixed with refrigerant in liquid form although the percentage of oil is much greater in this mixture than in the mixture entering the separator drum through the pipe 23. 'I'he refrigerant in the mixture which exists in the lower `portion of the drum 24 is used to refrigerate the drum and to accomplish this the mixture passes from the drum`24 through the exit pipe 40, a T 4|, a vscale trap 43, a control expansion .valve 44 and through the pipe 45 which connects with the inlet pipe 36 for the coil 36. Passing upwardly through the coil 36 the mixture of oil and refrigerant, now under suction pressure, leaves the separator drum 24through the exit pipe 31, past the thermostatic control 46, the hand valve 41 and finally into the suction line l5,` whence it returns to the system.

It will be understood from the operation described that the greater portion of the refrig@ erant of the total mixture of refrigerant and oil passing through the pipe 2| is separated in the drum 24 and goes into the evaporator l0 in a clarified condition. The balance of the refrigerant, together with the separated oil, by-passes the evaporator and from the oil separator drum,

goes directly into the plant suction line.

Valve 44 is controlled by the thermostat convalve such as designated at l2 in Fig. 1. 'I'he expansion valve 44 may be self controlled in vresponse to temperature conditions of the liquid leaving the drum 24 through the pipe 46. This will obviate the need for thethermostat 46 and electrical connections 43.

I claim:

1. The method of by-passing oil around an evaporator which comprises the initial passage of liquid refrigerant, containing oil. through a heat exchanger, thereafter .chilling and whirling said. liquid to clarify a portion thereof; feeding said chilled clarified portion through said heat exchanger and to the said evaporator and thence -into the plant suction line and utilizing the remainder of said original liquid refrigerant to ac-l complish said chilling during its passage with entrained oil to the plant suction line,

2. The method 'of separating oil from a liquid refrigerant which comprises the stepsv of simultaneous chilling and whirling of said refrigerant lto .congeal the oil therein and cause said oil to adhere to the surfaces encountered during its path through the'separator apparatus.

3. In a refrigeration system including a liquid refrigerantv line anda suction line, apparatus to by-pass oil around a refrigerating evaporator ed liquid refrigerant from said upper interior space through said heat exchanger to provide a liquid feed of refrigerantforl said evaporator; and an exit pipe for a mixture of oil and refrigerant from said drum to convey said mixture to said refrigerating coil and thereby cool said coil and drum during its passage therethrough to the said suction line.

HARRY A. pimms. 

